Flashcards in Toxicology Deck (72):
Ipecac? Gastric lavage?
V. rarely used. Gastric lavage - only with ET tube (AMS, uncooperative); prevent aspiration, laryngospasm.
Yes, immediately. Do not use with hydrocarbons, acids/alkalis. Does not tend to work well for lithium, K+, iron, some metals, alcohols. Risk - aspiration pneumonitis. Do not use cathartics.
Whole bowel irrigation (GoLYTLETY, Colyte)?
-lithium, heavy metals, iron
-multiple packets of drugs
-sustained release tablets
Must be able to sit on toilet.
Multiple doses of activated charcoal. Effective for theophylline, pentobarbital, carbamazepine, quinine.
ASA, lithium, methanol, ethylene glycol.
Theophylline, pentobarbital; rarely available.
Labs in Intoxication Pt
Bedside glucose, (+) naloxone, urine/blood toxicology; EKG, acetaminophen level (+NAS w/in 8 hr), CXR, KUB, LFTs, UA, acid-base status, serum Osms.
Toxidrome - Anticholinergic
S/S, Common Causes
Agitated delirium, visual hallucinations, mumbling speech, tachycardia, DRY FLUSHED SKIN, DILATED PUPILS, myoclonus, temp up, URINARY RETENTION, decreased bowel sounds --> seizures, dysrhythmias.
!!! Antihistamines, antiparkinsonism medication, atropine, scopolamine, amatadine, antipsychotics, antidepressants, mydriatics, skeletal muscle relaxants, many plants (jimsyn weed).
*** "Blind as a bat, mad as a hatter, red as a beet, hot as Hades (or hot as a hare), dry as a bone, the bowel and bladder lose their tone, and the heart runs alone." ***
Toxidrome - Sympathomimetic
S/S, Common Causes
Delusions, agitation, paranoia, tachycardia, HTN, hyperpyrexia, diaphoresis, piloerection, mydriasis, hyperreflexia --> seizures, dysrhythmias.
Cocaine, amphetamines, methamphetamines (MDA/MDMA, MDEA), OTC decongestants (ephedrine).
Toxidrome - Opiate/Sedative
S/S, Common Causes
Coma, resp depression, mitosis, hypoTN, bradycardia, hypothermia, acute lung injury, decreased bowel sounds, hyporeflexia, needle marks.
Narcotics, barbs, BZDs.
Toxidrome - Cholinergic
S/S, Common Causes
SLUDGE MM: Salivation, lacrimation, urination, diarrhea, GI distress, emesis, mitosis, muscle spasm.
DUMBBELSS: Diarrhea, urination, miosis, bronchospasm, bradycardia, emesis, lacrimation, salivation, sweating.
Organophosphate and carbamate insecticides, physostigmine, edrophonium, some mushrooms.
Unconscious OD Pt? Give...
dextrose + naloxone (2 mg in acute OD; multiple 0.2 mg doses in chronic opioid use to prevent withdrawal)
Anticholinergic Toxidrome? Give...
Physostigmine, 1-2 mg IV slowly. NEVER give in TCA OD (i.e., EKG w/ QRS widening, large R wave in aVR).
Digitalis Poisoning? Give...
Digoxin immune Fab (Digiband, Digitab), up to 10 vials, must wait 20 min for response.
Cholinergic Toxidrome? Give...
Atropine (dry pulmonary secretions) + pralidoxime (reverse skeletal m. toxicity).
BZD OD? Give...
Usually nothing...if acute BZD OD resulting in significant toxicity, give flumazenil. May cause BZD withdrawal, seizures. Give 0,2 mg...30 secs...0.3 mg...30 secs...0.5 mg - repeat up to total 3 mg.
Methanol/ethylene glycol poisoning? Give...
Ethanol and fomepizole - alcohol dehydrogenase blocking agents; prevent metabolism to toxic metabolites.
Acetaminophen OD? Give...
N-acetylcysteine, best if w/in 8 hrs. PO 140 mg/kg loading dose + 70 mg/kg q4hrs). IV 150 mg/kg in 200 ml D5W over 15 min loading dose + 50 mg/kg in 500 ml D5W over 4 hrs + 100 mg/kg in 1 L D5W over 16 hr.
EtOH Withdrawal? Give...
BZD (diazepam, lorazepam) +/– haloperidol for hallucinations.
Acute AWDs? Chronic AWDs?
AWDs = alcohol withdrawal seizure
Acute – Airway, 50% dextrose, BZD (IV + 2-days post seizure).
Chronic – (i.e., epileptogenic focus) phenytoin, etc.
PREVENT WITH BZDs!
Complications of chronic alcoholism or binge drinking...
EtOH-induced hypoglycemia, alcoholic ketoacidosis.
Complications of chronic alcoholism or binge drinking...
EtOH-induced hypoglycemia, alcoholic ketoacidosis. Note AKA can occur with ketoacidosis (met acidosis), hyperventilation (resp alk), and protracted emesis (met alk).
Chemical sedation in combative EtOHic.
Haloperidol, sedation without airways compromise or respiratory depression.
Ddx and Tx
Ddx (2 of following):
- Dietary deficiencies.
- Oculomotor abnormalities.
- Cerebellar dysfunction.
- AMS or mild memory impairment.
Tx - Thiamine IV + Mg
Methanol v. Ethylene Glycol Poisoning - Metabolism and Treatment
Methanol --> (ADH*) --> formaldehyde TOXIC --> formic acid --> (folate*) --> CO2 + H2O NON-TOXIC.
Methanol --> (ADH*) --> glycolic acid TOXIC --> (thiamine, VitB6/pyridoxine*) --> metabolites NON-TOXIC.
Methanol Poisoning - Ocular Toxicity
Retinal edema, hyperemia of disc, decreased visual acuity.
Na – (HCO3- + Cl-), nml 6-10.
2*Na + glucose/18 + BUN/2.8 + ethanol?4.3, positive is > 10 mOsm.
Methanol & Ethylene Glycol Poisoning - Treatment
Airway, sodium bicarb, antidotes – ethanol & 4-methylpyrazole (4-MP) – competitively block conversion to toxic metabolites.
Give ethanol/fomepizole (saturate ADH) + folate or thiamine/VitB6 +/– hemodialysis?
Dose of 4-MP...
15 mg/kg q12h; increased to 15 mg/kg q4h during dialysis. Treat for 48 hr.
Indications for dialysis methanol/ethylene glycol?
Blood level > 50 mg/dL (or > 25 mg/dL), metabolic acidosis refractory to treatment, pending renal failure, visual symptoms in methanol ODl.
- Minimal Acute Toxic Dose
- 150 mg/kg
- N/V, tinnitus, vertigo, fever, diaphoresis, confusion, hyperventilation, pulm edema --> delirium, seizures, coma.
- Salicylate levels, time 0, 6h, etc.
- Acute respiratory alkalosis --> 12-24 hr --> anion gap metabolic acidosis.
- Indications for Dialysis
- Alkaline diuresis (IV bicarb). Activated charcoal + cathartic; lavage if w/in several hrs of ingestion. Cool, give K+, give D50, O2/CPAP/BiPAP/ET+PEEP (pulmonary edema).
- Dialysis if... refractory metabolic acidosis (pH < 7.1), renal failure, CP dysfunction (pulm edema, dysrhythmias, cardiac arrest), CNS dysfunction (coma, seizures, cerebral edema), acute level > 130 mg/dL at 6 hr post-ingestion.
Pt appears to be getting worse but blood levels are decreasing - Why?
Blood levels X tissue levels. In acidic blood, ASA remains un-ionized and more can penetrate the BBB.
4 Phases of APAP Toxicity
- Time, S/s, Labs
1. < 24 hr – Asymptomatic; anorexia, N/V, diaphoresis – toxic APAP level.
2. 24-72 hr – RUQ pain – mild inc. LFTs.
3. 3-5 days – N/V, jaundice, encephalopathy, oliguria – large inc. LFTs, coagulopathy, azotemia, hypoglycemia, hypoPO4.
4/. 1 week – Potentially, gradual resolution w/ improvement in lab values.
What is rapidly depleted in APAP OD that accounts for accumulation of toxic metabolites?
Prediction of hepatotoxicity in APAP OD.
> 7.5 gm adult, 140 mg/kg child.
NAC (glutathione substitute), best if administered w/in 10 hrs.
Dilute 1:5 with water (20% soln). Loading dose 140 mg/kg, maintenance 70 mg/kg q4h for 17 additional doses. Vomit w/in 1 hour of dose? Give dose again. Can also give IV but may cause N/V, flushing – slow infusion, give Benadryl; angioedema/anaphylaxis – stop infusion, Benadryl, steroids, Epi.
1. Clean wound.
2. + 20 IU/kg human rabies IG (50% in wound, 50% in gluteal muscle).
3. + 1 mL vaccine in deltoid muscle or anterolateral thigh on days 0, 3, 7, and 14.
Strep > PCN-resistant S. aureus.
Eikenella - PCN or ampicillin; resistant to semi-synthetic penicillins, clinda, 1st gen cephalosporins.
Why is smoke inhalation dangerous?
CO & CO2 --> hypoxemia. Toxic gases.
4 Stages of Smoke Inhalation
1. 1-12 hr, acute respiratory distress (bronchospasm, edema).
2. 6-72 hr, ARDS (noncardiogenic pulmonary edema).
3. 60-120 hr, strangulation 2/2 cervical eschar formation.
4. 72 hr+, pneumonia (S. aureus, Pseudomonas, Gm negative).
First Signs of Smoke Inhalation
Cough, sputum production, hoarseness.
Smoke Inhalation Evaluation/Treatment
Asymp - Observe for a few hrs, struct return precautions (cough, SOB, fever).
Symp - Confirm with bronchoscopy.
Higher fluid requirement but more likely to develop pulm edema - Gide fluid resuscitation on clinical appearance.
Do NOT need a CXR - will be negative at first.
- Fire in enclosed space.
- CO level.
- Non-rebreather high flow mask O2 (decreases t1/2 from 4-5h to 1h); HBO if pregnant with CO > 15, any neuro abnormality, any cardiac ischemia.
- Smoke from burning furniture or fabric (wool, silk, polyurethane).
- Increased lactate.
- HBO, Lilly cyanide antidote kit, hydroxocobalamin.
Hydroxocobalamin = VitB12; combined with cyanide to form non-toxic cyanocobalamin.
Duration of Action?
CNS depression only... 0.2-0.4 mg initial dose, repeat up to 2 mg (up to 10 mg for some synthetics?).
Apneic...2 mg initial dose.
Chronic user? Infuse 0.1 mg; wakes pt without inducing withdrawal.
Note: 0.8 mg IM = 0.4 mg IV
*** Duration of action = 40 - 75 min; need repeat dosing!!!!
Disposition in Opiate/Opioid OD + Naloxone?
After last dose of naloxone...
Injection of Long-Term Opioids, 4-8h
Ingestion of Long-Term Opioids, 24h+
Complications (inadequate ventilation, etc.), admit.
- Yawning, anxiety, lacrimation, rhinorrhea, diaphoresis, mydriasis, N/V, diarrhea, piloerection, abd pain, myalgia.
- Symptomatic - IVF, sedation, antiemetics, antidiarrheal agents +/– clonidine 0.1-0.2 mg PO.
Body Stuffers v. Packers, Treatment
Suffers - Activated charcoal.
Packers - Xray/CT, activated charcoal, polyethylene glycol soln (Golytely) / enemas --> repeat CT +/– surgery.
Other Considerations in Synthetic Opioid OD
Other Complications of Opioid OD
Non-cardiogenic pulm edema (pink frothy sputum, cyanosis, rales, bilateral alveolar infiltrates).
Sedative/Hypnotic OD, Treatment
Supportive! ABCDs, activated charcoal (1 gm/kg w/in 1 hr), exclude other causes of presentation.
Flumazenil, 0.2-0.5 mg IV repeat up to 5 mg.
ACUTE, SINGLE-AGENT ODs ONLY! Can induce seizures in multi-agent ingestions or chronic BZD users.
Complications of Mushrooms
GI distress, hepatic failure, seizures.
- Hyperthermia, met acidosis, HTN, seizures, dysrhythmias, rhabdomyolysis.
- Calm environment, supportive care; BZD for seizures and agitation; antipsychotics for hallucinations and psychosis.
Treatment for Cocaine-Induced CP
PTX, pneumomediastinum, MI.
Complications of Methamphetamines and MDMA/Ecstasy (designer amphetamine)
HTN, dysrhythmia, intracranial hemorrhage, seizures, hyperthermia. Especially, if taken during rave in case of MDMA. Long-term neurotoxicity in chronic MDMA use. MDMA associated with severe hypoNa+ (increased H2O intake during rave, drug-induced secretion of ADH).
Treatment Stimulant Toxicity, esp. HTN
- Calm - BZD (agitation, seizures)
- Cool - cooling blankets, cool IVF
- Complications - evaluate for potential complications
HTN? BZD. Severe HTN emergency? BZD + nitroglycerin. +/– Phentolamine, nitroprusside, CCB rarely as needed,
*** AVOID Beta-Blockers!!! Dogma: Allows for unopposed-alpha stimulation --> severe HTN, coronary artery vasoconstriction.
Cocaine + EtOH?
Depresses myocardial contractility.
Stimulant-Induced OTD (Occult Triad of Death)
Acidemia, rhabdo, pyrexia.
Peds - Lomotil
Anticholinergic --> opioid toxidrome.
Peds - Toxic Dose of TCA
>/= 15 mg/kg, approx. one adult dose.
Peds - Sulfonylura OD
Octreotide (antidote) + dextrose (as needed to maintain blood glucose)
Pads - Toxic Dose of Salicylates (ASA & OIL OF WINTERGREEN aka methyl salicylate)
BOTH pends and adults...acute toxicity at 150 mg/kg, serious toxicity at 300 mg/kg.
* Brady + HTN
* Pre-Synaptic Alpha2 Agonists (clonidine, oxymetazoline, tetrahydrozoline) - transient.
* Brady + HypoTN + Narrow QRS
* Pre-Synaptic Alpha2 Agonists (clonidine, oxymetazoline, tetrahydrozoline).
* Beta-blockers, CCB, cardiac glycosides.
* Sedative/hypnotics, opioids, BZDs/barbs (minimal).
* Organophosphates and carbamates.
* Brady + HypoTN + Wide QRS
* Lidocaine, tocainide.
* B-blockers w/ Na-channel effects (propranolol, acebutolol, metoprolol).
* CCBs, cardiac glycosides - severe toxicity.
* Propafenone, flecainide.
* Quinidine, procainamide, disopyramide.
** Hyperkalemia from cardiac glycosides, BB, and K+sparing diuretics.
Antidote for Na+ channel blockade.
Na bicarbonate 1-2 mEq/kg bolus; x2 if QRs fails to narrow. + Hyperventilation to pH 7.5 and hypertonic saline.
+/– IVF/vasopressors for HTN, BZD for seizures, ET tube for AMS.
Tx CCB OD
HypoTN - IVF boluses.
Brady - atropine or pacing; inotropes (dopamine, NE, Epi).
Calcium gluconate, calcium chloride (central line or large IV; risk of vein necrosis).
* Tachy + HypoTN + Wide QRS
Summarize CCB/BB OD Tx
Supportive, symptomatic. ABCs, IVF, pressers. Atropone, glucagon, Ca, high-dose insulin.